BACKGROUND Dural venous sinus thrombosis (DVST) is an increasingly recognized cause of a wide array of neurological symptoms, with outcomes that range from complete recovery to death. The condition of approximately 23% of patients with DVST will worsen after initial presentation, as a result of restricted venous outflow and venous hypertension, but early identification of this subset is challenging. A venous collateral scale (VCS) that grades alternative drainage routes may improve prediction of clinical deterioration. OBJECTIVE To examine the ability of the VCS system to accurately identify patients with DVST who will experience clinical worsening, based on their imaging at presentation. METHODS From our institutional database, we identified patients with DVST on dedicated venous imaging between January 2010 and July 2016. A VCS was created and calculated from venous imaging at presentation by two reviewers blinded to subsequent data. RESULTS The 27 patients who met the inclusion criteria for this study had a median age of 42 years and 14 (52%) were female. Initial symptoms included headache without hemorrhage in 30% and focal deficit in 30%. Transverse sinus occlusion was present in 70% and superior sagittal sinus occlusion in 41%. VCS was 0 in 11%, 1 in 37%, and 2 in 52%. A lower VCS was significantly associated with clinical worsening both from time of initial symptom onset (77% vs 29%, VCS 0-1 vs 2, p<0.05) and during hospitalization (62% vs 0%, VCS 0-1 vs 2, p<0.01). In multivariate analysis, VCS but no other presenting features was significantly associated with in-hospital worsening (OR=2, p<0.01). CONCLUSIONS The type and quality of venous collaterals influence outcome in DVST. VCS helps to identify patients whose condition is likely to deteriorate and may need additional aggressive interventions.